Half Baked (R, 1998)

This is the kind of movie that only pot smokers (current, former, or potential) will enjoy. The fragile plot is kept alive by the constant insider jokes, which range from clever (comedian Steven Wright plays Man-on-the-Couch -- an unknown guy who just sleeps on the roommates' couch throughout the whole movie), to dumb (the guys get a dog high).

Despite the movie's thin premise, Dave Chappelle is actually a very smart comedian, so he sticks all sorts of tiny details into the film that enrich it slightly. For example, in an attempt to get accepted into a clinical marijuana trial he tells a scientist that he's qualified because his grandfather was part of the Tuskegee experiments (when the US government used poor African-American men as test subjects beginning in the 1930s resulting in the unecessary death of many). These tidbits together with Chappelle's silly likeability save the film from horridness.